Doctor of Philosophy (Ph.D.)
William E Cooke
Matrix Assisted Laser Desorption/Ionization (MALDI) is a time-of-flight mass spectrometry commonly used to detect a wide mass range of biomarkers. However, MALDI requires a high laser pulse energy to create ions with a mass higher than 50,000 Daltons. That high laser energy increases the net ion production but it also degrades the instrument's mass resolution. This project uses a Room Temperature Ionization Liquid (RTIL) as a liquid matrix with a self healing surface instead of a standard crystal matrix to increase shot to shot reproducibility, enabling a systematic study of the origin of the resolution degradation. This study shows that the main source of the resolution degradation is the ionic space charge which delays the ejection of ions into the acceleration region, essentially increasing the ionization pulse time to be as long as hundreds of nanoseconds. This study includes simulation and experimental results to document this effect.
© The Author
Qu, Guangzhi, "Resolution Limits of Time-of-Flight Mass Spectrometry with Pulsed Source" (2016). Dissertations, Theses, and Masters Projects. Paper 1477068405.